Digital anti-counterfeiting software method and apparatus

ABSTRACT

An authenticatable object comprises a surface having a latent hidden image embossed therein. The latent image is an encoded version of an authentication image and comprises a plurality of elements applied to the surface with a predetermined frequency. The latent hidden image is configured for optical decoding by a decoder having a decoder frequency corresponding to the predetermined frequency.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.12/880,622, filed Sep. 13, 2010, now U.S. Pat. No. 8,437,578, which is acontinuation of U.S. application Ser. No. 10/025,531 filed Dec. 29,2004, now U.S. Pat. No. 7,796,753, which is a continuation of U.S.application Ser. No. 09/005,736 filed Jan. 12, 1998, now U.S. Pat. No.6,859,534, which is a continuation-in-part of U.S. application Ser. No.08/564,664, filed Nov. 29, 1995, now U.S. Pat. No. 5,708,717, all ofwhich are incorporated herein by reference in their entirety. Thisapplication is related to U.S. application Ser. No. 11/868,607, filedOct. 6, 2007, now U.S. Pat. No. 7,466,876, and to U.S. application Ser.No. 11/372,514, filed Mar. 10, 2006.

FIELD OF THE INVENTION

This invention relates generally to a method and apparatus, asimplemented by a software program on a computer system, for producingcounterfeit-deterring scrambled or coded indicia images, typically in aprinted form. This method and system are capable of combining a sourceimage with a latent image so the latent image is visible only whenviewed through a special decoder lens.

BACKGROUND INFORMATION

To prevent unauthorized duplication or alteration of documents,frequently there is special indicia or a background pattern provided forsheet materials such as tickets, checks, currency, and the like. Theindicia or background pattern is imposed upon the sheet material usuallyby some type of printing process such as offset printing, lithography,letterpress or other like mechanical systems, by a variety ofphotographic methods, by xeroprinting, and a host of other methods. Thepattern or indicia may be produced with ordinary inks, from special inkswhich may be magnetic, fluorescent, or the like, from powders which maybe baked on, from light sensitive materials such as silver salts or azodyes, and the like. Most of these patterns placed on sheet materialsdepend upon complexity and resolution to avoid ready duplication.Consequently, they add an increment of cost to the sheet materialwithout being fully effective in many instances in providing the desiredprotection from unauthorized duplication or alteration.

Various methods of counterfeit-deterrent strategies have been suggestedincluding Moire-inducing line structures, variable-sized dot patterns,latent images, see-throughs, bar-codes, and diffraction based holograms.However, none of these methods employs a true scrambled image or theadded security benefits deriving therefrom.

This same inventor earlier disclosed a novel system for coding anddecoding indicia on printed matter by producing a parallax panoramagramimage. These principles and embodiments of U.S. Pat. No. 3,937,565,issued Feb. 10, 1976 are hereby incorporated by reference. The indiciawere preferably produced photographically using a lenticular line screen(i.e. a lenticular screen) with a known spatial lens density (e.g. 69lines per inch). A specialized auto-stereoscopic camera might be used toproduce the parallax image such as the one described in this inventor'sU.S. Pat. No. 3,524,395, issued Aug. 18, 1970, and U.S. Pat. No.3,769,890, issued Nov. 6, 1973.

Photographic, or analog, production of coded indicia images has thedrawback of requiring a specialized camera. Also, the analog images arelimited in their versatility in that an area of scrambled indicia isgenerally noticeable when surrounded by non-scrambled images. Also, itis difficult to combine several latent images, with potentiallydifferent scrambling parameters, due to the inability to effectivelyre-expose film segments in generating the scrambled, photographic image.

Systems such as described in U.S. Pat. Nos. 3,937,565; 3,769,890;4,092,654; 4,198,147; and 4,914,700 disclose methods of preventingcounterfeiting by forming a parallax panoramagram image of a subject,known as Scrambled Indicia® system, typically photographically through alenticular line screen (i.e. a lineticular screen).

Scrambled images resist ready reproduction by photographic orxerographic techniques inasmuch as the extent of scrambling or encodingprovided by these system is controlled by a large variety of parameterspeculiarly under the control of the originator of the scrambled orencoded image. Yet, the scrambled image can be unscrambled for visualexamination using a decoder that is substantially a duplicate of thelenticular screen used to form the original image.

The systems and methods described in the above-identified prior artpatents typically employ an autosteroscopic camera for photographingartwork so as to produce a scrambled parallax panoramagram thereof.Specifically, the camera includes a lenticular screen and aphotosensitive element is placed in the combined image plane of thecamera formed by the objective lens and the lenticular screen. The imageof the graphic to be encoded is focused on the photosensitive element inthe image plane of the camera with a small aperture stop that increasesthe depth of focus. The lenticular screen and photosensitive element arethen moved longitudinally along the optical axis of the camera withrespect to the objective lens of the camera to one edge of, but withinthe limits defining, the depth of focus. The photosensitive element isthen exposed to the light projected from the graphic while thelenticular screen and photosensitive element are moved togetherlaterally relative to the objective lens of the camera to exposesuccessive portions of the photosensitive element underlying the screen.The relative movements are such that the point image of the subjectcenter of the graphic will be recorded in the center of thephotosensitive element as a blurred spot which is moved progressively inthe course of the relative movement of the objective lens, lenticularscreen, and photosensitive element.

The resulting image formed on the photosensitive element is a lenticulardissection of the image of the graphic, as well as an image in which thedisplacement between the subject center and the second conjugate pointintroduces a scrambling factor so that the scrambled or encoded imagecannot readily be identified by unaided vision.

As an alternative security printing system, diffraction-based imagessuch as embossed holograms have been incorporated into the surface ofcredit cards and the like. Although this tactic initially reduced theincidence of forgeries, the technology for reproducing and incorporatingembossed holograms has become sufficiently widespread that its use inpreparing security devices has been impaired.

Another optical documentary security and object authentication device isthe optically variable device, such as a KINEGRAM®, available fromLandis & Gyr communications (Switzerland) Corp., which anotherdiffraction-based system that can be fabricated using an embossingtechnique and presents distinctive dynamic optical effects easilyvisualized by an observer. The system is suggested for use as ahigh-level optical security device to protect banknotes, passports,Visas, ID-cards, and other security documents against counterfeit andtampering. The image of a KINEGRAM® is created by a plurality ofinvisibly small elementary areas of reflective micro-profiles, each ofwhich diffract illuminating light. The elementary areas are used tocompose lines and graphical elements. For each area or line element,micro-profile size and shape, the angles of diffraction and diffractionintensities are calculated to produce the overall image.

Accordingly, a method and apparatus are needed whereby the photographicprocess and its results are essentially simulated digitally via acomputer system and related software. Additionally, a system is neededwhereby scrambled latent images can be integrated into a source image,or individual color components thereof, so that the source image isvisible to the unaided eye and the latent image is visible only upondecoding. Also needed is the ability to incorporate multiple latentimages, representing different “phases”, into the source image for addedsecurity.

SUMMARY OF THE INVENTION

The present invention provides a software method and apparatus fordigitally scrambling and incorporating latent images into a sourceimage. The latent image—in digitized form—can be scrambled for decodingby a variety of lenticular lenses as selected by the user, with eachlens having different optical properties such as different linedensities per inch, and/or a different radius of curvature for thelenticulas. Different degrees of scrambling might also be selectedwherein the latent image is divided up into a higher multiplicity oflines or elements. For decoding purposes, the multiplicity of elementswould be a function of the lens density.

The source image is then rasterized, or divided up into a series oflines equal in number to the lines making up the scrambled latentimages. Generally, when hard copy images are printed, the image is madeup of a series of “printers dots” which vary in density according to thecolors found in the various component parts of the image. The softwaremethod and apparatus of the present invention, takes the rasterizedlines of the source image and reforms them into the same general patternas the lines of the scrambled latent image. Hence, where the sourceimage is darker, the scrambled lines are formed proportionately thicker;where the source image is lighter, the scrambled lines are formedproportionately thinner. The resulting combined image appears to theunaided eye like the original source image. However, since the componentrasterized lines are formed in the coded pattern of the scrambled latentimage, a decoder will reveal the underlying latent image. Due to thehigh printing resolution needed for such complex scrambled lines,attempts to copy the printed image by electromechanical means, orotherwise, are most often unsuccessful in reproducing the underlyinglatent image.

As a result of this digital approach, several different latent imagescan be scrambled and combined into an overall latent image, which canthen be reformed into the rasterized source image. This is achieved bydividing the rasterized lines into the appropriate number of images (orphases) and interlacing the phased images in each raster line element.Each individual latent image might be oriented at any angle andscrambled to a different degree, so long as the scrambling of each imageis a functional multiple of the known decoder frequency. Alternatively,the grey scale source image might be divided up into primary componentprinting colors (e.g. cyan, magenta, yellow, and black, or CMYK; red,green, blue, or RGB). Single color bitmap formats might also be used forcertain applications. A scrambled latent image, or a multi-phased image,could then be individually reformed into each component color. Uponrejoining of the colors to form the final source image, the decoder willreveal the different latent images hidden in the different colorsegments.

The present invention also allows the option of flipping each of theelements of the latent image after it has been divided or scrambled intoits elemental line parts. As has been discovered by the inventor, thisunique step produces relatively sharper decoded images when each of theelements is flipped about its axis by one-hundred and eighty (180)degrees. This same effect was achieved by the process of U.S. Pat. No.3,937,565, and the cited stereographic cameras therein, through theinherent flipping of an object when viewed past the focal point of alens. The flipped elemental lines are then reformed into the rasterizedsource image. While enhancing the sharpness of the latent image, theflipping of the elements has no adverse, or even noticeable, effect onthe appearance of the final coded source image. Moreover, by combiningtwo images consisting of one image where the elements are flipped andanother where they are not flipped, the appearance of a spatialseparation of the two images will occur upon decoding.

As needed, the source image might simply consist of a solid color tintor a textured background which would contain hidden latent images whenviewed through the proper decoder. Such solid, tinted areas mightfrequently be found on checks, currency, tickets, etc.

Other useful applications might include the latent encoding of aperson's signature inside a source image consisting of that person'sphotograph. Such a technique would make it virtually impossible toproduce fake ID's or driver's licenses through the common technique ofreplacing an existing picture with a false one. Other vital informationbesides the person's signature (e.g. height, weight, identificationnumber, etc.) might also be included in the latent image for encodinginto the source image.

Still other useful applications might include, for example, thefollowing: credit cards, passports, photo-identification cards,currency, special event tickets, stocks and bond certificates, bank andtravelers checks, anti-counterfeiting labels (e.g. for designer clothes,drugs, liquors, video tapes, audio CD's, cosmetics, machine parts, andpharmaceuticals), tax and postage stamps, birth certificates, vehiclerestoration cards, land deed titles, and visas.

Thus, an objective of the present invention is to provide acounterfeit-deterrent method and apparatus, as implemented by a softwareprogram on a computer system, for producing scrambled or coded indiciaimages, typically in a printed form. The coded image can then be decodedand viewed through a special lens which is matched to the softwarecoding process parameters.

A further objective of the present invention is to provide acounterfeit-deterrent method and apparatus, as implemented by a softwareprogram on a computer system, wherein a source image is rasterized, andthe latent image is broken up into corresponding elemental lines, andthe rasterized source image is reconstructed according to the codedpattern of the scrambled image.

Yet a further objective of the present invention is to provide acounterfeit-deterrent method and apparatus, as implemented by a softwareprogram on a computer system, wherein the source image is converted intoa grey scale image for incorporation of a latent scrambled image.

Still another objective of the present invention is to provide acounterfeit-deterrent method and apparatus, as implemented by a softwareprogram on a computer system, wherein the grey scale source image isfurther separated out into its component color parts for possibleincorporation of latent scrambled images into each component color part,with the parts being rejoined to form the final encoded source image.

A related objective of the present invention is to provide acounterfeit-deterrent method and apparatus, as implemented by a softwareprogram on a computer system, wherein the elemental lines of thescrambled image may be rotated or flipped about their axis as necessary,or as selected by the user.

A further objective of the present invention is to provide acounterfeit-deterrent method and apparatus, as implemented by a softwareprogram on a computer system, wherein the “single phased” the scrambledimage consists of a first latent image which has been sliced andscrambled as a function of a user selected decoder density andscrambling factor.

Yet another objective of the present invention is to provide acounterfeit-deterrent method and apparatus, as implemented by a softwareprogram on a computer system, wherein the “two phased” scrambled imageis sliced as a function of a user selected decoder density, and eachslice is halved into two sub-slices, and the first and second latentimages are alternately interlaced in the sub-slices, with each latentimage scrambled by a user selected scrambling factor.

Still another objective of the present invention is to provide acounterfeit-deterrent method and apparatus, as implemented by a softwareprogram on a computer system, wherein the “three phased” scrambled imageis sliced as a function of a user selected decoder density, and eachslice is divided into three sub-slices, and the first, second, and thirdlatent images are alternately interlaced in the sub-slices, with eachlatent image scrambled by a user selected scrambling factor.

Yet another objective of the present invention is to provide acounterfeit-deterrent method and apparatus, as implemented by a softwareprogram on a computer system, wherein an “indicia tint” is producedwhich is similar to a two phased SI, but with one source file, and everysecond sub-slice of the input image is the complimenter of the firstsub-slice.

A further objective of the present invention is to provide acounterfeit-deterrent method and apparatus, as implemented by a softwareprogram on a computer system, wherein the source image consists of asolid color or tint pattern with the scrambled image incorporatedtherein, but the elemental lines are flipped only where a letter orobject occurs in underlying latent image.

Still another objective of the present invention is to provide acounterfeit-deterrent method and apparatus, as implemented by a softwareprogram on a computer system, wherein the latent image is encodeddirectly into a certain visible figure on the source image, thuscreating a “hidden image” effect.

Yet another objective of the present invention is to provide acounterfeit-deterrent method and apparatus, as implemented by a softwareprogram on a computer system, wherein a bitmap source image is used(instead of a grey scale image) to create hidden images behind singlecolor source images or sections of source images.

Still another related objective of the present invention is to provide acounterfeit-deterrent method and apparatus, as implemented by a softwareprogram on a computer system, wherein a multilevel, 3-dimensional reliefeffect is created by applying different scrambling parameters to animage and its background.

Another related objective of the present invention is to provide acounterfeit-deterrent method and apparatus, as implemented by a softwareprogram on a computer system, wherein “void tint” sections might beproduced and the word “void,” or similar such words, would appear acrossdocuments if attempts are made to photocopy them.

Yet another possible objective of the present invention is to use thesoftware program and computer system to produce the equivalent of “watermarks” on paper products.

Still another possible objective of the present invention is to use thesoftware program and computer system to produce, or to aid in producing,holographic images through line diffraction techniques.

Another embodiment of the invention is to disclose a device and methodof security printing and object authentication by encoding an ordinarilyrecognizable indicium, i.e., a distinctive mark, by forming a parallaxpanoramagram image of the recognizable indicium through a lenticularline screen. The resulting encoded image is a scrambled lineticulardissection of an image of the recognizable indicium. The scrambled imageis then transformed into a diffraction-based image, such as a hologram.

The device enhances documentary security and object authentication byuse of an encoded parallax panoramagram and means defining an embosseddiffracting surface incorporating the encoded parallax panoramagram, theportion of that surface which incorporating the panoramagram havinglight-diffracting properties different than the light-diffractingproperties of adjacent portions of the surface. In one embodiment of theinvention, that surface includes a hologram. In another embodiment thatportion of said surface incorporating the panoramagram is embossed witha diffraction grating. The encoded parallax panoramagram is preferablyformed by use of a digital printer in a manner similar to theaforementioned embodiment.

Surprisingly, although one might expect that rendering ScrambledIndicia® type images in a form based upon diffraction of light wouldseriously impair or prevent decoding through the usual simple lenticularscreen, such decoding nevertheless remains completely unimpaired and thesystem retains the same ease and simplicity of use of the originalScrambled Indicia® system notwithstanding that another order of securityhas been imposed on the system.

The method also includes the step of forming a security graphic image byat least juxtaposing an unencoded graphic and the encoded indicium toform a composite image, a diffraction grating having diffractiveproperties that vary in accordance with intensity variations in thecomposite image. The composite image includes copy-resistant content,such as a guilloche. In another embodiment, the encoded indicium isunobtrusively incorporated substantially within the unencoded graphic soas to induce a viewer of the security graphic image to believe that theencoded indicium is a feature of the unencoded graphic.

In another preferred embodiment, a diffraction grating is created byforming a reflective surface that includes a first plurality of regionsof a diffraction grating of a first brazing angle, and a secondplurality of regions of a diffraction grating of a second brazingangles, the first and second plurality of regions being distributed overthe reflective surface so as to form the final security graphic image.

In all cases, the encoded indicium of the security graphic image can bedecoded to authenticate the security graphic image using a decoder thatis substantially a duplicate of the lenticular line screen used for theencoded indicium.

The invention also includes a method for security printing and objectauthentication wherein an embossed hologram is created that includes asurface with diffractive properties that vary over the surface inaccordance with intensity variations in an unencoded graphic image, andthen a security graphic image is formed by embossing the embossedhologram with a die having a plurality of regions raised in relief so asto form a diffraction grating having distinct diffraction propertieswithin each region, and distributed in accordance with an encodedindicium.

The invention also includes a method for security printing and objectauthentication wherein an embossed hologram is created having a surfacewith diffractive properties that vary the surface in accordance withintensity variations in a security graphic image that includes anencoded indicium.

It is a general object of the alternate embodiment of the presentinvention to provide a device and a method for enhancing documentarysecurity and object authentication based upon principles of optics ofthe type described that significantly overcomes the problems of theprior art.

A more specific object of the present invention is to provide means forsignificantly reducing the likelihood of counterfeiting and unauthorizedmodification of documentary security and object authentication devicesbased upon diffraction of light, such as holograms, KINEGRAMS®, andblazed reflection phase gratings.

Another object of the invention is to provide means for thwartingunauthorized reproduction by sophisticated optical techniques ofdiffraction-based documentary security and object authenticationdevices.

Other objectives and advantages of this invention will become apparentfrom the following description taken in conjunction with theaccompanying drawings wherein are set forth, by way of illustration andexample, certain embodiments of this invention. The drawings constitutea part of this specification and include exemplary embodiments of thepresent invention and illustrate various objects and features thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a “one phase” example of the Scrambled Indicia (SI) processwherein an output image is sliced into elements as a function of thefrequency of the decoding lens and the scrambling factor (or zoomfactor, or base code) as selected by the user.

FIG. 2( a) shows a scrambled “P” (above) with its resulting elementsenlarged 400% (below) wherein the elements have been flipped 180 degreesabout their vertical axes.

FIG. 2( b) shows the scrambled “P” (above) of FIG. 9( a) with itsresulting elements enlarged 400% (below) wherein the elements have notbeen flipped or altered.

FIG. 3 shows a “two phase” SI example of slicing the output image,wherein the width of the slice is one half of the one phase example,with every odd slice being from a ‘source one’ file, and every evenslice being from a ‘source two’ file.

FIG. 4 shows a “three phase” SI example of slicing the output image,wherein the width of the slice is one third of the one phase example,with every third slice being from the same source input file.

FIG. 5 shows a comparison of the one, two, and three phase scrambled andcoded results.

FIG. 6 shows a series comparison of scrambled images as a function ofincreasing lens frequency (or line density per inch) from 10 through100.

FIG. 7 shows a series comparison of scrambled images as a function ofincreasing zoom factor (or base code) ranging from 30 through 250, for agiven lens frequency.

FIG. 8 shows a series comparison of two phased scrambled images whereinthe first latent image and the second latent image are rotated withrespect to each other ranging from 10 through 90 degrees.

FIG. 9 shows the steps involved to encode, as hidden images, twoseparate scrambled indicia patterns into two separate base colors asextracted from the original source image.

FIG. 10 shows a flow chart of the steps relating to the process as shownin FIG. 9.

FIG. 11 shows an example hardware configuration for running the S.I.software and performing the SI process.

FIG. 12A is a first portion of a flow chart of the overall operation ofthe S.I. software.

FIG. 12B is a second portion of a flow chart of the overall operation ofthe S.I. software, which in combination with FIG. 12A, is referred toherein as FIG. 12.

FIG. 13 the introductory screen for the scrambled indicia software(SIS).

FIG. 14 shows the series of options appearing on the generalized screenfor a one phase type SI selection.

FIG. 14( a) shows the choices resulting from clicking on the File Menuoption.

FIG. 14( b) shows the resulting screen when either load or save isselected from the File Menu option.

FIG. 15 shows and details further options of the generalized screen fora one phase SI selection.

FIG. 15( a) shows the Browse option screen as selected from the screenshown in FIG. 15.

FIG. 16 shows the generalized screen for a two phase type SI selection.

FIG. 17 shows the generalized screen for a three phase type SIselection.

FIG. 18 shows the generalized screen for an indicia tint type SIselection.

FIG. 18( a) shows an “indicia tint” example of slicing the output image,wherein the width of the slice is one half of the one phase example,with every other sub-slice being the complimenter of the previoussub-slice input.

FIG. 19 shows the generalized screen for a hidden image type SIselection.

FIG. 20 shows the generalized screen for a multilevel type SI selection.

FIG. 21 shows the generalized screen for an S. I. Raster type selection.

FIG. 22 shows examples of rastering techniques with the accompanyingcircles indicating an enlarged view of a portion of the overall pattern.

FIG. 23 is illustrative of prior art in which FIG. 23 is an example of arecognizable indicium; FIG. 23B is an example of the recognizableindicium of FIG. 23 after being encoded as a parallax panoramagram imagethat is a lineticular dissection of the recognizable indicium; FIG. 23Cis a lenticular screen used to create the parallax panoramagram image ofFIG. 23B; FIG. 23D is an enlarged partial cross-section of a lenticularscreen for decoding the indicium of FIG. 23B; FIG. 23E illustrates thedecoded or unscrambled recognizable indicium as it appears to a viewerthrough the lenticular screen of FIG. 23D and FIG. 23F is an example ofan unencoded graphic.

FIG. 24 is an example of a security graphic image showing the encodedrecognizable indicium unobtrusively incorporated within the unencodedgraphic;

FIG. 25 is a diagram showing prior apparatus that can be used to recorda holographic image of at least an encoded indicium to be used informing an embossed hologram that incorporates the encoded indicium;

FIG. 26 is a schematic, exaggerated cross-section through one embodimentof the present invention showing sections of the surface embossed with adiffraction grating at a given blaze angle and sections emboxxed with ahologram:

FIG. 27 is a schematic, exaggerated cross-section through anotherembodiment of the present invention showing through another embodimentof the present invention showing sections of the surface embossed with adiffraction grating at a two different blaze angles;

FIG. 28 is a schematic, exaggerated cross-section through yet anotherembodiment of the present invention showing the surface embossed with ahologram; and

FIG. 29 is a top plane view of a tamperproof foil having a hidden imageformed from a computer driven mechanical etching machine.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Although the invention has been described in terms a specific embodimentwith certain alternatives, it will be readily apparent to those skilledin this art that various modifications, rearrangements and substitutionscan be made without departing from the spirit of the invention. Thescope of the invention is defined by the claims appended hereto.

The Scrambled Indicia (SI) process involves rasterizing, or dividing upinto lines, a source or visible image according to the frequency (ordensity) of a lenticular decoder lens. The number of lines is also afunction of the scrambling factor, or zoom factor, as applied to alatent or secondary image. After the latent image is processed andscrambled, a set of scrambled lines exists which can then be combinedinto the rasterized lines of the visible image. The visible image isthus reformed, or re-rasterized, according to the pattern of thescrambled latent image lines. Where the visible image is darker, thescrambled lines are made proportionately thicker in re-forming therasterized lines of the visible image; similarly, where the visibleimage is lighter, the scrambled lines are made proportionately thinner.As a result, a new visible image is created, but with the encoded,latent, SI pattern being visible “underneath” when viewed through atransparent decoder lens.

Referring now to FIG. 1, certain example details of the process areshown. In this example, one latent image is processed into a visiblesource image, and this process is generally referred to as a “one phase”SI operation. In any SI operation, an output image is a function of thedecoder lens density. An output image 2 is shown which is sliced up intoelemental slices, or segments, of width h. (See reference 4). Each slicewidth h is a function of several factors such as density and base code.

As for lens density, the inventor has assigned reference names to lenseswith various frequencies (or line densities per inch), including forinstance, the following: D-7X with 177 lines/inch; D-7 with 152.5lines/inch; D-6 with 134 lines/inch; D-9 with 69 lines/inch. (Seereference 6). The software for performing this process also provides an“.times.2” (or doubling factor, df) option which doubles the effectiveline density, and hence divides the output image up into twice as manyslices. The resulting SI image will still be decodable by the selectedlens because the number of lines is an even multiple of the frequency ofthe lens.

The output image slice, having width h, is processed as a function ofthe input slice width i (see reference 8). In turn, width i is afunction of width h, the lens density, and a base code factor (orscrambling factor) as selected by the user. These formulas are asfollows:

df=2(if “.times.2” selected); 1 (by default)

o=h*density/100 (See reference 10)

i=o*base code(B) (See reference 8)

Rearranging these formulas, the value for h becomes:

$h = \frac{\left( {1/B} \right)*100}{{Density}*{df}}$

Hence, as the value for the base code and/or the density is increased,the width h will decrease. A larger base code, or scrambling factor,therefore creates more lines and results in a more distorted orscrambled image.

Additionally, the SI process allows the option of flipping 12 the inputslice to affect the sharpness of the image. Referring now to FIG. 2( a),the letter “P” is shown scrambled 30 according to the S.I. process. Animage 34 enlarge by 400% further shows the characteristic elements 38.In this instance the elements have each been individually flipped 180degrees about their vertical axis. FIG. 2( b) shows the same example “P”32, and enlarged version 36 where the elements have not been flipped.When viewed through the proper decoder lens for these particular S.I.parameters, the flipped “P” will appear sharper, or more visuallydistinct, than the unflipped “P”. For any scrambled image, the softwareprovides the user the option of flipping or not flipping the elements,as further detailed below.

Referring now to FIG. 3, a “two phase” SI process is shown whereby themethod is similar to that for the one phase SI. In this case, however,each slice of width h is further divided into a first and secondsub-slice. The elemental lines of first and second scrambled images willbe stored by the software program in ‘source one’ and ‘source two’files. In the resulting output image, the odd slices 14 are composed ofelemental lines from the source one file, and the even slices 16 arefrom the source two file. Up on decoding, the first and second scrambledimages will appear independently discernable.

Referring now to FIG. 4, a “three phase” SI process is shown as similarto the one and two phase SI processes. In this case, width h is dividedinto three parts. The first, second, and third scrambled images arestored in three computer source files. In the resulting output image,every third slice 18, 20, and 22 comes from the same respective first,second, or third source file. Again upon decoding, the first, second,and third scrambled images will appear independently discernable.

Referring to FIG. 5, a comparison is shown of the one, two, and threephase scrambled results for a given lens density and base code. FIG. 6shows a comparison of the scrambled results for a given base code and avarying set of lens densities ranging from 10 through 100 lines perinch. As the lens density increases, the relatively width of eachelemental line decreases and causes the scrambled image to be harder todiscern. In FIG. 7, the lens density is fixed while the zoom factor, orbase code, is increased through a series of values ranging from 30-250.Similarly as per the formulas above, as the base code is increased, therelative width of each elemental line decreases and causes the scrambledimage to be harder to discern. As shown, the discernability of thescrambled image for a zoom factor of 30 is far greater than for a zoomfactor of 250.

Another benefit or feature of multiple phasing is that each latent imagecan be oriented at a different angle for added security. Referring nowto FIG. 8, a series of two phase images is shown where the first latentimage remains fixed and the second latent image is rotated, relative tothe first image, through a series of angles ranging from 10-90 degrees.

Referring now to FIG. 9, an example of the versatility offered by asoftware version of the S.I. process is shown. In this example, apostage stamp is created whereby the S.I. process incorporates twodifferent latent images, oriented 90 degrees to each other, into twodifferent base colors of the visible source image. The visible sourceimage—as comprised of its original RGB colors—is scanned, as a digitalhigh resolution image, into a program such as ADOBE PHOTOSHOP. The imageis then divided into its component color “plates” in yet anothercommonly used color format CMYK, wherein the component images of Cyan42, Magenta 44, Yellow 46, and Black 48 are shown. The versatility ofthe S.I. software allows for the easy combination of a latent S.I. imagewith any one component color of the visible image. In this case, thelatent invisible image 50 with the repeated symbol USPS is scrambled andmerged with the Cyan color plate 42. The resulting Cyan color plate52—as described above—will show the original visible image in arasterized pattern to the unaided eye, but the latent invisible imagewill be encoded into the rasterized pattern. A second latent invisibleimage 54 with the repeated trademark SCRAMBLED INDICIA (of thisinventor) is merged with the Magenta color plate 44 to produce theencoded Magenta image 56. The final visible image (similar to 40) willthen be re-composed using the original Yellow and Black plates alongwith the encoded Cyan and Magenta plates.

Referring now to FIG. 10, an example flow chart of the steps performedby the S.I. software in FIG. 10 are shown. The source image is firstdigitized 41 and then divided out into its component CMYK colors 43.Each color plate 45, 47, 49, and 51 can be independently operated on byany of the S.I. process implemented. In this case, a hidden imagetechnique (or rasterization in single color) is performed. The targetcolor plates are rasterized 53, 55 and the S.I. scrambling process isapplied to the first latent image 57 and the second latent image 59. Thefirst scrambled image is then merged with the rasterized Cyan colorplate 61 and the second scrambled image is merged with the rasterizedMagenta color plate 63. The final output image is a created byre-joining the encoded Cyan and Magenta color plates with the unalteredYellow and Black color plates 65. In this example, only the Cyan andMagenta colors were encoded. Other examples might choose to encode onecolor, three colors, or all four colors.

While this process might be implemented on any computer system, thepreferred embodiment uses a setup as shown in FIG. 11. Various imagefiles, as stored in “tif” format 60, are fed into a SILICON GRAPHICSINC. (SGI) workstation 62 which runs the S.I. software. While thesoftware might run on any computer capable of handling high resolutiongraphics, the SGI machine is used because of its superior speed andgraphical abilities. The files are opened by the S.I. software and thescrambled indicia types, values, and parameters are set by the programuser 64. Encoding algorithms are applied by the S.I. software to mergelatent images with visible images to create a new scrambled “tif” file66. The new “tif” file is then fed into a MACINTOSH computer 68 forimplementation into the final design program, wherein the file isconverted into an Encapsulated PostScript (EPS) file format 70. Thefinished design is then sent to an output device of choice 72 which iscapable of printing the final image with the resolution necessary tomaintain and reveal the hidden latent images upon decoding. Thepreferred output device is manufactured by SCITEX DOLVE.

Referring now to FIG. 12, a flow chart of the overall operation of theS.I. Software is shown. Upon entering the program 80, a set of interfacesettings are either created 82, or read 86 from a default file 84. Theuser is then presented with a series of input screens for selecting thetype of S.I. process to perform, along with the related parameters forperforming such an operation. One option might be to save the settingsalready selected 90 into a user selected file 92. A related option wouldbe to load settings already saved 94 into a user selected file 96.

As already described, the user might choose to perform a one, two, orthree phase S.I. process. Accordingly, the user would indicate theappropriate source files on which to perform the S.I. process andindicate that such a one, two, or three phase calculation (shown as 98,100, and 102) should be performed. Other S.I. operations which could beselected for calculation, would include a “tint” method 104, a “hidden”method 106, a “multilevel” method 108, and a “raster” method 110.Otherwise, the user might choose to exit the program 112, or re-enterthe selection process 114.

Upon transitioning past the selection process, the program checks166-128 the various input settings selected the user. The programdetects errors 117-129 relating to each selection, and displays anappropriate error message 131 as appropriate. Based upon the inputsettings selected, the various operations will be performed, e.g.scramble with one phase method 130 and save the one phase results to anoutput file 132; scramble with two phase method 134 and save the twophase results to an output file 136; scramble with three phase methodand save the three phase results to an output file 140; scramble withtint method 142 and save the tint method results to an output file 144;scramble with hidden method 146 and save the hidden results to an outputfile 148; scramble with multilevel method 150 and save the multilevelresults to an output file 152; or scramble with raster method 154 andsave the raster results into an output file 156. The results of any ofthese methods can then be displayed and viewed 160 (if desired) via aresulting viewer window 162. Tonal sound indicators 166 can alsoindicate the progress of the software if selected 164.

The S.I. software uses a variety of user interface screens whichfacilitates choosing which type of S.I. process will be performed, andunder which parametric conditions. FIG. 13 shows the introductory screenupon entering the SIS program which shows the user the ownership rightsassociated with the program. The user interface for the SIS is basedupon the “X window” environment. It is similar to most GUI (GraphicalUser Interfaces). When the user moves the mouse pointer to a choicefield and holds the mouse button down, the user will get a pop down orpop up window. This window will allow the user to make even morechoices.

FIG. 14 shows the basic user interface screen associated with performingan SI operation. When the user clicks on the File Menu option, thechoices in FIG. 14( a) will appear (e.g. About SIS, Load Settings, SaveSettings, Sound, and Quit) When the user chooses either load or savefrom the file menu, the screen in FIG. 14( b) will appear. The user maydrag the slider bar 200 or click on the arrow keys 201 to move throughthe list of available files. Moreover, the user can use the directorybar buttons 202 to shift backwards in the shown directory hierarchy. The“filter” button 203 brings up another window 204 which allows the userto specify which type of files to view; for instance the “wildcard”designator “*” could be used with “*.tif” to bring up all “tif” filesfor possible selection from among the listed files. Once the desiredfile is found, the “OK” button 205 accepts and loads/saves the file.Either cancel button 206 ends the current operation.

Furthermore, if the user activates the Sound setting, the SIS programwill provide verbal cues to let the user know what's going on;otherwise, the SIS program will remain silent during operation. The usercan quit the SIS software at anytime by selecting quit, or executing anAlt-Q keystroke.

Referring again to FIG. 14, the “decoder” box 170 shows the type ofdecoder selected (e.g. D-7×). The “type” box shows the scramble type 176selected (e.g. one phase S.I., two phase S.I., hidden image S.I., etc.).The “density” slider bar 172 allows the user to control the line weightof the image that is created during the encoding process. The featurewill affect both the “positive” (darkened) and “negative” (white) spaceof the object being encoded. This value can be adjusted based upon whatyou are encoding and what the final print destination will be. The “basecode” slider bar 174 allows the user to control the amount of scramblethat is applied during the encoding stage, as described above. The“flip” box allows the user to turn each individual scrambled element by180 degrees about its vertical axis. This option helps hide the originalitem when that item is of a simple enough nature to see even after thescramble. In other words, sometimes when scrambling a single word or afew characters, the letters are still discernable despite the scramblingprocess applied. By flipping the elements, a deeper scramble can oftenbe achieved which can still be decoded by the same lens. Also, asmentioned before, flipping the elements often produces a sharper decodedcharacter.

FIG. 15 shows the same basic user interface screen with furtherexplanations of user interface boxes. The “source file” box 178 allowsthe user to directly enter the file name to which the program isapplying the scramble. The “destination file” box 180 allows the user todirectly enter the name of the file for the finished output. Both thesource file and destination file boxes have “browse” buttons 182 whichpull up yet another box 184 (FIG. 15( a)) for selecting possible sourceand destination files. In the browse box, the user may use arrows, orthe slider bar, to scroll through the file directories and locate andselect a particular file. The “filter” box 185 allows the user to selecta specific file name and have the program search for it. The“resolution” box 186 indicates the resolution of the final output image.This number should be matched to the resolution of the destinationprinting device. The “view” option box 188 allows the user to decidewhether or not to see the scrambled image upon completion of the S.I.calculation. The “LZW” option box 190 allows the user to save filesusing compression. Compression keeps the overall size of the filessmaller and conserves disk storage space. The “calculate” button 192allows the user to click on this bar when ready to finally apply theS.I. scrambling process.

FIG. 16 shows a similar screen for performing a two phase S.I.operation. However, this screen provides entry boxes for two sourcefiles 210, where the latent images are interlaced into a two phasedscrambled image. With the two phased example, the user can select adifferent base code for each image. This is especially useful when theuser wants to create an overlay of two different sets of text that willbe viewed together, yet be seen as separate words when decoded. A“restraint” option box 212 is provided for linking the first and secondimages together whereby the same base code will be applied to eachimage. The remainder of the options are similar to those describedabove.

FIG. 17 shows a similar screen for performing a three phase S.I.operation. This screen provides three source file input boxes 214wherein each input image can have a different base code applied, or thesame base code can be applied to all by activating the restraint option216.

Referring now to FIG. 18 the interface screen for performing an “indiciatint” operation is shown. Unlike the hidden image S.I. (below), theindicia tint will flow as smoothly as possible through the image,ignoring tonal variations. This image might be thought of as a “monotonescramble.” Referring now to FIG. 18( a), an output image is shown(similar to FIG. 2) which is similar to a two phase S.I., but with onlyone input file. In this instance, every second sub-slice 222, 224 of theoutput image is the complimenter of the immediate previous inputsub-slice. The complimenter means, for example, that when the input isblack, the complimenter is white, if the input is red, the complimenteris cyan, etc.

FIG. 19 shows the interface screen for a “hidden image” S.I. operationwhich provides input boxes for a latent image 218 and a visible image220. This operation allows the user to mix two images together where oneof the images becomes latent to the other which is visible. This effectwill allow the latent image to be visible only when viewed through thedecoder. Hidden image S.I. also allows use of an additional file tocompensate for image offset. The hidden image S.I. is similar to the twophase S.I. (described above) and the indicia tint (below) except thatthe output background is a picture instead of white. The first step isto copy the visible image to the output image. After this, the method issimilar to the indicia tint, but the density parameter controls thevisibility of the image. Also, the hidden image technique is similar tothe S.I. Raster (below), but a bitmap (single color) image is usedinstead of a grey scale image.

FIG. 20 shows the user interface screen for multilevel S.I. operation.The multilevel S.I. creates a scrambled image that contains a sense ofdepth perception. This type of scramble allows the user to set both aminimum base code 226 and a maximum base code 228. This particularversion of the SIS program uses two images, one image called the textureimage 222 and another called a depth image 224. During encoding, thetonal values of the depth image elements will cause a scrambling variantin the elements of the texture image. This variant will give the decodedimage the illusion of depth, hence the name multilevel S.I.

For example, this multilevel technique can simulate a 3-dimensional(“3-D”) camera effect by placing a face in the depth image and applyingless base code, while flipping the elements for added sharpness. Thebackground would be placed in the texture file which would have morebase code applied for more scrambling effect, and with no flipping ofthe elements. By superimposing these two scrambled images upon eachother, the decoded face would appear to be sharper and have more depththan the surrounding background. Hence the face would appear to “float”,thereby creating a 3-D effect.

Referring now to FIG. 21, the interface screen for an S.I. Rasteroperation is shown. The S.I. Raster allows the user to mix two imagestogether where one of the images becomes latent 230 to the other whichis visible 232. The latent image will interlace with the visible imagefollowing the grey scale values of that image. This effect will allowthe latent image to be visible only when viewed through a decoder.Additionally, the latent image might consist of a one, two, or threemulti-phased image as created using previous interface screens formulti-phased images and saved in an appropriate file.

One of the most useful applications for the S.I. Rastering technique iswhere the visible image is a photograph and the latent image might be asignature of that person. Using the SIS program, the visible image canbe rasterized and then the signature image can be scrambled and mergedinto the visible image raster pattern. The resulting encoded image willbe a visible image of a person's photograph, which when decoded willreveal that person's signature. The latent image might include othervital statistics such as height, weight, etc. This high security encodedimage would prove to be extremely useful on such items as passports,licenses, photo ID's, etc.

The processes described above have used line rastering techniques asderived from the suggested lenticular structure of the decoding lens.Other rastering techniques might also be used, which would beaccompanied by corresponding decoder lenses capable of decoding suchrastered and scrambled patterns. Referring now to FIG. 22, a series ofexample rastering techniques are shown which could similarly be used toencode scrambled images into rasterized visible source images.Accompanying each type of rastering is a circle showing an enlargedportion of the raster. The example types include: double line thicknessmodulation; line thickness modulation II; emboss line rastering; relief;double relief; emboss round raster; cross raster; latent round raster;oval raster; and cross line raster. Another technique, cross embossedrastering, might use one frequency of lens density on the vertical planeand yet another frequency on the horizontal plane. The user would thencheck each latent image by rotating the lens. Yet another techniquewould include lenses which, varying in frequency and/or refractivecharacteristics across the face of a single lens. Hence different partsof the printed matter could be encoded at different frequencies andstill be decoded by a single lens for convenience. Undoubtedly manyother rastering types exist which are easily adaptable to the SISencoding techniques.

Regardless of the type of rastering used, a variety of other securitymeasures could be performed using the SIS program and the underlyingprinciples involved. For instance, the consecutive numbering systemfound on tickets or money might be scrambled to insure further securityagainst copying. The SIS program might also digitally generate scrambledbar encoding. A Method and Apparatus For Scrambling and Unscrambling BarCode Symbols has been earlier described in this inventors U.S. Pat. No.4,914,700, the principles of which are hereby incorporated by reference.

Yet another common security printing technique includes using complexprinted lines, borders, guilloches, and/or buttons which are difficultto forge or electronically reproduce. The SIS program can introducescrambled patterns which follow certain lines on the printed matter,hence the inventor refers to this technique as Scrambled Micro Lines.

The security of the Scrambled Indicia might be further enhanced bymaking 3 color separations in Cyan, Magenta, and Yellow of the imageafter the S.I. process has been performed. These colors would then beadjusted to each other so that a natural grey could be obtained on theprinted sheet when the colors are recombined. The inventor refers tothis process as “grey match.” Hence, while the printed image wouldappear grey to the unaided eye, the decoded image would appear in color.The adjustment of the separations to maintain a neutral grey becomes yetanother factor to be controlled when using different combinations ofink, paper, and press. Maintaining these combinations adds another levelof security to valuable document and currency.

Still another possible use of the SIS program would be to createinterference, or void tint, combinations on printed matter. Thistechnique will conceal certain words, like “void” or “invalid” on itemssuch as concert tickets. If the ticket is photocopied, the underlyingword “void” will appear on the copy and hence render it invalid to aticket inspector. The SIS software would provide an efficient and lowcost alternative to producing such void tint patterns.

The SIS program might also be adapted to produce watermark-type patternswhich are typically introduced to paper via penetrating oil or varnish.Furthermore, the SIS program might be applicable to producing hologramsvia line diffraction methods. Again, the SIS program would prove to bemore efficient and cost effective for producing such results.

Now referring to a second embodiment of the invention, the prior art ofwhich is shown in FIG. 23, wherein like numerals refer to like parts,illustrates in FIG. 23 an example of a typical recognizable indicium 310can be used with the present invention. Recognizable indicium 310 shownincludes the letter “A”, and may also include other letters to formrecognizable words, such as “Florida”, or other symbols, or anyrecognizable or identifiable graphic image. Although contrastingbackground 314 is shown as white, and therefore is in maximumcontrasting intensity relationship with indicium 310, background 314 canbe chosen so as to be in a contrasting relationship selected to render aparallax panoramagram image more difficult to interpret, or to renderthe parallax panoramagram image of indicium 310 more difficult torecognize as being a parallax panoramagram image. The minimum contrastrequired between indicium 310 and background 314 is dependent onlighting conditions under which the image of indicium 310 is to berecorded, as well as the sensitivity of the photosensitive surface onwhich the image of indicium 310 is to be recorded.

FIG. 23B shows recognizable indicium 310 of FIG. 23 encoded as parallaxpanoramagram image 310′ which includes an encoded letter “A′ againstencoded background 314′. Encoding as a parallax panoramagram image canbe accomplished using, for example, the apparatus disclosed in U.S. Pat.No. 4,092,654.

FIG. 23C shows transparent lenticular screen is used in the above-citedencoding process to provide encoded indicium 310′. As is well known,screen 316 includes a plurality of cylindrical lenticular 318 and isessentially a lineticular screen. As shown in FIG. 23D, to reconstruct,unscramble, or decode the encoded image of FIG. 16B, transparentlenticular screen 316′, having a plurality of cylindrical lenticular318′ of the negative images can be registered with a high degree ofprecision.

According to this embodiment of the invention, a security graphic imageis formed of a parallax panoramagram image incorporated into, orjuxtaposed with, an unencoded graphic image. As with the aforementionedembodiment, this can be formed through the use of a software method andapparatus for digitally scrambling and incorporating latent images intosource image. Such juxtaposition, for example, includes forming aholographic image of one or both of the parallax panoramagram image andthe unencoded graphic image, wherein the holographic image portraysthese images as residing at differing apparent depth or planes. Whereone of the images is holographic, the other image can be formed by areflective diffracting surface, a transmissive diffracting surface, asecularly reflecting surface, or a diffusely reflecting surface, or anycombination thereof.

In another preferred embodiment of the present invention, a securitygraphic image 328 is formed by unobtrusively incorporating a parallaxpanoramagram image within an unencoded graphic image, so as toeffectively hide the parallax panoramagram image as shown in FIG. 24.For example, while region 330 with the dark region 326 of FIG. 23Fappears to be a body of water extending behind the skirt of a womanstanding in the foreground, in security graphic image 328, parallaxpanoramagram image 330 replaces at least part of dark region 326 of theunencoded graphic image 320 of FIG. 23F so as to appear to be anintegral part of unencoded graphic image 320, e.g., an image of a bodyof water having reflections off its surface. Parallax panoramagram 330is actually an encoding of the recognizable indicium “FLORIDA” whichincludes the letter “A” as shown in FIG. 23 as well as other lettersthat are encoded in a similar manner.

In an alternate embodiment, the unencoded graphic portion of a securitygraphic image can include copy-resistant content, such as a guilloche. Aguilloche resembles a “spirograph”, and may be difficult to copy becauseit incorporates fine, precise, and intricate detail.

According to the invention, a surface is formed having diffractiveproperties that vary over the surface in accordance with intensityvariations in a graphic image such as is shown in FIG. 24. As notedearlier herein, the parallax panoramagram image within the securitygraphic image is unexpectedly still decidable, even when the imageexists in the form of variations in the diffractive properties of asurface, such as diffraction due to variations in the brazing angle overthe surface of a reflective diffraction grating, or diffraction inducedby the surface of an embossed hologram.

In yet another preferred embodiment illustrated in FIG. 27, thediffractive surface includes a plurality of regions 329 of a reflectivediffraction grating of a first brazing angle, and a plurality of regions331 of a reflective diffraction grating of a second brazing angle. Thefirst and second plurality of regions 329 and 331 are distributed overthe reflective surface so as to form a security graphic image, such asthe security graphic image 322 of FIG. 24.

The invention also includes devices in which a diffractive surface isformed with a portion having diffractive properties that vary inaccordance only with an encoded graphic image, and another surfaceportion having some combination of diffusing, absorbing, translucent, orsecularly reflecting properties, wherein a parallax panoramagram imageis printed in juxtaposition with respect to the diffractive portion, oron a non-diffracting portion of the surface that is surrounded by thediffractive portion using, for example, light absorbing, diffusing, orreflecting ink, paint, or pigment.

With reference to FIG. 25 according to the invention, security graphicimage 332 can be rendered entirely as an embossed hologram. Securitygraphic image 332, which may include or consist entirely of an image ofa scramble or encoded recognizable indicium, is formed on a flatsubstrate. As is well-known in the holographic are (see, for example,Holography Market Place, Third Edition, Kluepfel and Ross, Eds., 1991.Ross Books, Berkeley, Calif. 94704, incorporated herein by reference),to form a hologram of the security graphic image 332, as shown in FIG.18, the security graphic image is illuminated by a first portion 334 ofa laser beam 336, provided by a beam-splitter 337, a mirror 338 and alens 340. Reflected light 342 from the security graphic image 332interferes with a second portion of the laser beam 344 via a mirror 346and a lens 348, forming interference fringes. A recording material orlight-sensitive plate 350, typically a silver halide emulsion,dichromated gelatin, a photopolymer, a photoresist or the like, forexample, is disposed for recording the pattern of interference fringesproduced thereby. For example, where plate 350 is a photoresist, thephotoresist is etched, and then plated with a metal such as silver,nickel or the like, for example. The layer of metal deposited on plate350 then includes holographic patterns in relief, and can be removed toserve as a metal mold, known as a “shim”. The shim serves as a metalstamping die for stamping the holographic pattern into, for example, ahigh-molecular weight polymer or plastic. A plastic sheet or film havingthe holographic patter embossed thereon can be used as a transmissiveembossed hologram, or can be coated or laminated with a reflective ormirror-like backing to produce a reflective embossed hologram.

Typically, the reflective or mirror-like backing is applied to theembossed side of the plastic sheet or film, and the reflective embossedhologram is viewed through the unembossed side of the sheet or film.

In an alternate embodiment of the invention, security graphic image 332includes unencoded graphic material, such as a guilloche, or otherfinely detailed graphic material from which an embossed holograph isprepared. After the holographic pattern of such unencoded graphicmaterial has been recorded and then embossed into a plastic sheet orfilm using a holographic shim or die, a second shim is embossed into theplastic sheet or film. The second shim was prepared by incorporating anencoded parallax panoramagram of a recognizable indicium, and bears, inrelief, regions of diffraction gratings of distinct diffractionproperties distributed over the surface of the shim in accordance withintensity variations in the parallax panoramagram. For example, thepattern of regions of diffraction gratings can be a reflectiondiffraction grating having regions of a first brazing angle and regionsof a second brazing angle. After the second shim is embossed into theplastic sheet film, the plastic sheet or film can be coated or laminatedwith a reflective or mirror-like backing to produce a reflective surfacehaving regions of a plurality of diffractive properties, includingholographic properties.

FIG. 29 is a top lane view of a tamper-proof foil 351 having latenthidden image 352 formed from a computer driven mechanical etchingmachine. The hidden image 352, in this example the numeral 93 indicatesthe year of creation, can be viewed only by use of a decoder lens 354having frequency capable of revealing the latent hidden image. The imagemay be digitally scanned into a computer system by use of a computerscanner.

The ability to conceal any type of hidden image allows a point of useinput including a persons name, birth date, social security number andso forth. The hidden image including variable information may be placedon bank notes, stock certificates, bonds, travelers checks, lotterytickets, passports, airline tickets, gift certificates, bank checks,postal money orders, credit cards, photo identification, driverslicenses, postage stamps, and like documents.

The process of formation includes calculating the line/inch, employingthe appropriate reduction factor, and sizing the image to a decoderhaving a particular frequency. The image may be screened or manipulatedusing normal commercial graphic arts screening and special effecttechniques.

It is to be understood that while I have illustrated and describedcertain forms of my invention, it is not to be limited to the specificforms or arrangement of parts herein describe and shown. It will beapparent to those skilled in the art that various changes may be madewithout departing from the scope of the invention and the invention isnot to be considered limited to what is shown in the drawings anddescribed in the specification.

What is claimed is:
 1. An automated method for digitally encoding at least one digital image into a source image so that the at least one digital image is not discernible within the source image without application of a reader having a frequency pattern, the method comprising: obtaining the at least one digital image having a first pattern of line elements, the first pattern of line elements corresponding to the selected frequency pattern of the reader; obtaining the source image having a second pattern of line elements; applying an encoding algorithm to incorporate the at least one digital image into the source image; and generating a revised source image comprising the first pattern of line elements and the second pattern of line elements, wherein the revised source image substantially replicates the source image when viewed without the reader, and wherein the first pattern of line elements are configured in the revised source image to be hidden until viewed with the reader having the selected frequency pattern.
 2. The automated method according to claim 1 wherein the first pattern of line elements and the second pattern of line elements are regularly spaced.
 3. The automated method according to claim 1 wherein the first pattern of line elements and the second pattern of line elements are regularly spaced and form a two dimensional array of non-linear shapes.
 4. The automated method according to claim 1 wherein applying the encoding algorithm includes interlacing the first pattern of line elements and the second pattern of line elements.
 5. The automated method according to claim 1 further comprising: forming the revised source image on a substrate.
 6. The automated method according to claim 5 wherein forming the revised source image on the substrate includes printing the revised source image on the substrate.
 7. The automated method according to claim 2, wherein the first pattern of line elements and the second pattern of line elements are regularly spaced to correspond to the reader having the frequency pattern that matches the first pattern of line elements.
 8. The automated method according to claim 7, wherein the first pattern of line elements is different from the second pattern of line elements.
 9. The automated method according to claim 1, further comprising: obtaining a second digital image having a third pattern of line elements, the third pattern of line elements being oriented at a predefined angle relative to the digital image having the first pattern of line elements; applying a second encoding algorithm to incorporate the second digital image into the source image; and generating a second revised source image comprising the first pattern of line elements, the second pattern of line elements, and the third pattern of line elements, wherein the second revised source image substantially replicates the source image when viewed without the reader, and wherein the first pattern of line elements and the third pattern of line elements are configured in the second revised source image to be hidden until viewed with the reader having the selected frequency pattern.
 10. The automated method according to claim 9, wherein the second encoding algorithm is different from the encoding algorithm and wherein the third pattern of line elements is different from the first pattern of line elements and the second pattern of line elements.
 11. The automated method according to claim 6, wherein printing the revised source image on the substrate is performed using at least one of an ink, a magnetic ink and a fluorescent ink.
 12. A non-transitory computer storage medium having software code stored thereon, the software code being configured to cause a computer to execute a method for digitally encoding at least one digital image into a source image so that the at least one digital image is not discernible within the source image without application of a reader having a selected frequency pattern, the method comprising: obtaining the at least one digital image having a first pattern of line elements, the first pattern of line elements corresponding to the selected frequency pattern of the reader; obtaining the source image having a second pattern of line elements; applying an encoding algorithm to incorporate the at least one digital image into the source image; and generating a revised source image comprising the first pattern of line elements and the second pattern of line elements, wherein the revised source image substantially replicates the source image when viewed without the reader, and wherein the first pattern of line elements are configured in the revised source image to be hidden until viewed with the reader having the selected frequency pattern.
 13. The non-transitory computer storage medium according to claim 12 wherein the first pattern of line elements and the second pattern of line elements are regularly spaced.
 14. The non-transitory computer storage medium according to claim 12 wherein the first pattern of line elements and the second pattern of line elements are regularly spaced and form a two dimensional array of non-linear shapes.
 15. The non-transitory computer storage medium according to claim 12 wherein applying the encoding algorithm includes interlacing the first pattern of line elements and the second pattern of line elements.
 16. The non-transitory computer storage medium according to claim 12, wherein the first pattern of line elements and the second pattern of line elements are regularly spaced to correspond to the reader having the frequency pattern that matches the first pattern of line elements.
 17. The non-transitory computer storage medium according to claim 16, wherein the first pattern of line elements is different from the second pattern of line elements.
 18. The non-transitory computer storage medium according to claim 12, further comprising: obtaining a second digital image having a third pattern of line elements, the third pattern of line elements being oriented at a predefined angle relative to the digital image having the first pattern of line elements; applying a second encoding algorithm to incorporate the second digital image into the source image; and generating a second revised source image comprising the first pattern of line elements, the second pattern of line elements, and the third pattern of line elements, wherein the second revised source image substantially replicates the source image when viewed without the reader, and wherein the first pattern of line elements and the third pattern of line elements are configured in the second revised source image to be hidden until viewed with the reader having the selected frequency pattern.
 19. The non-transitory computer storage medium according to claim 12 further comprising sending a signal to a printer to form the revised source image on a substrate.
 20. The non-transitory computer storage medium according to claim 12, wherein sending the signal to the printer includes selecting at least one of an ink, a magnetic ink and a fluorescent ink for printing the revised source image. 